KotlinFunctionComposition

FunctionsComposition.kt

val xMinus3 = {x: Int -> x - 3}

val composedFull = compose(::xPlusX, ::add5To, ::xMulX)

val composed4 = compose(xMinus3, ::xPlusX, ::add5To, ::xMulX)

fun <R> compose(vararg funs: (R) -> R): (R) -> R = { x: R ->
    funs.reduceRight { acc, function -> { acc(function(it)) } }(x)
}

fun xPlusX(x: Int) = x + x

fun add5To(x: Int) = x + 5

fun xMulX(x: Int) = x * x

fun main(vars: Array<String>) {

    println(composedFull(6))

    println(composed4(6))
}